feat(updater): Configurable min ratio

- `UPDATER_MIN_RATIO` variable
- `-minratio` flag for CLI operation

internal/configuration/sources/env/helpers.go

@@ -38,6 +38,15 @@ func envToInt(envKey string) (n int, err error) {
 	return strconv.Atoi(s)
 }
 
+func envToFloat64(envKey string) (f float64, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return 0, nil
+	}
+	const bits = 64
+	return strconv.ParseFloat(s, bits)
+}
+
 func envToStringPtr(envKey string) (stringPtr *string) {
 	s := getCleanedEnv(envKey)
 	if s == "" {

internal/configuration/sources/env/updater.go

@@ -18,6 +18,11 @@ func readUpdater() (updater settings.Updater, err error) {
 		return updater, err
 	}
 
+	updater.MinRatio, err = envToFloat64("UPDATER_MIN_RATIO")
+	if err != nil {
+		return updater, fmt.Errorf("environment variable UPDATER_MIN_RATIO: %w", err)
+	}
+
 	updater.Providers = envToCSV("UPDATER_VPN_SERVICE_PROVIDERS")
 
 	return updater, nil